Many of the concepts that appear in the larger mosques of the region are repeated in miniature in the small, community-level mosques of the region. The mosques at Sebi and Kara, towns on or near the Niger River, contain prayer halls, patios, and minarets created with familiar mud-brick masonry techniques. The minarets of both structures, which rise above the mosques' mihrabs, are their most distinctive features: heavily buttressed and pyramidal at Sebi, boxy and tower-like at Kara. The walls of the Kara prayer hall also include pinnacles that are reminiscent of larger mosques in the region. The flat roofs of both prayer halls also include damage systems to sluice water away from the mob-brick structure in times of heavy rain.